The use of parity checking for error detection in digital systems is well established. While parity checking may be applied to many situations, the application of parity checking to arithmetic operations is of particular interest. Generally, any arithmetic operation has at least two operands from which a result is derived. This result may be a quotient, product, sum, difference, etc. Each of the operands and results may have their parity separately checked. In some operations, the parity of the result corresponds to the parity of one or more operands, although there is no simple correspondence for other operations between the parity of the result and the parity of the operand. Prior to this invention, parity of the result has been determined either by separately computing parity on the result per se or by correcting for the effect on parity of the operation performed on the operands.